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[Phys-L] For pot watchers: is it a conspiracy?



If you have never done this (below), you are a theoretician!

Have you ever sat and watched a counter register hits
supposedly occurring randomly in time, like a radiation
counter? That is, of course, a rhetorical question. Well, my
son David was doing just that for an agonizingly long time
while watching results come in from the Swift gamma ray burst
instrument, wondering why the instrument had quit working. I
enclose a snippet from the Swift Mission Director's Status
Report Log
http://swift.gsfc.nasa.gov/docs/swift/operations/status_log.html
to describe this seemingly non-Poissonian run of luck:

July 20, 2005

Swift has continued to amaze us with its record of burst
discoveries. We've learned first hand what 'random' truly
means. From June 7 to July 1, the BAT detected no new GRBs.
After July 1, we had no GRBs until July 12. Since July 12,
the BAT has found seven new bursts! So in these six weeks,
we've seen eight bursts [which is not too far from the
average rate of 100 per year] but almost all of them are
in the last week!

Swift is apparently working fine, so this lacuna is real. I
leave it as an exercise for the reader to calculate the *a
priori* odds on this observation. I suspect David did the
calculation several times, apprehensively, during the apparent
hiatus. He did share his concern with me during that time.

Leigh
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